Suppression of Gravitational Structure Formation by Cosmological Accretion Heating

As increasingly precise information about the spectrum of the cosmicmicrowave background fluctuations is gathered with balloon and satelliteexperiments, interest has grown in foreground sources of opacity affectingthese observations. One potentially important source is electron scatteringproduced by a post-recombination luminosity source, which would significantlyattenuate the higher harmonics in the spectrum. If such an ionization sourceexists, then it would also heat the universe, hence increasing the Jeans massand suppressing early gravitational structure formation. Here we consider theeffects of such heating. We concentrate on one type of ionization source:luminosity generated by accretion onto primordial compact objects. We show thatif such objects generate enough luminosity to affect the CMB power spectrum,then they would produce enough heat to prevent the formation of 1 sigmacollapsed objects until redshifts of about 5, significantly less than theredshift at which baryonic collapse could otherwise occur. Such processes wouldleave signatures detectable by upcoming instruments such as NGST, SIRTF, andSWIFT.Comment: 17 pages including 3 figures, accepted by Ap